That's an interesting point, the only 4-door classic Mopars I've driven have been C-bodies which obviously have longer doors. I'm 6'1" and didn't have issues with those but I could see A-bodies being kinda tight.
You think our fourdoors are tight? You should see some of the little English fourdoor cars.
I was looking at a fourdoor Austin gasser for a while. Basically used the rear doors for driver access. Only problem was, it was about a foot and a half long,..... if that.